An Eligible Mate
by unforth
Summary: Dean Winchester and Castiel Novak grew up on neighboring estates. It was a no-brainer that they'd end up mated until they both presented as omegas. Their presentation didn't change their feelings, nor their shared belief that Castiel was actually an alpha, but "biology didn't lie" and they were forbidden from being together. Now Dean has come of age...


It's time for Writing Prompt Wednesday! This story is from the theme for two weeks ago - I'm just a wee bit behind – but we'll be back on schedule tomorrow! Anyway, the theme was "…but we're already dating AUs"

 **What is Writing Prompt Wednesday?**

Writing Prompt Wednesday is a feature I run on my Tumblr. Followers, readers and friends suggest themes for AUs, and I come up with a list of prompts based on the suggested them. Then, based on those prompts, anyone who wants to join in writes up a short story (or a long story, I guess) and posts it to Tumblr (or AO3, or , or wherever) and tags it Writing Prompt Wednesday!

You can read more about Writing Prompt Wednesday, and read this week's entries, at my Tumblr: unforth-ninawaters.

This week, I chose this prompt (though my idea goes off the rails a bit from what the prompt suggests…):

 _Our parents have decided to arrange marriages for us, which fricken sucks since we've been together for a long time, except apparently the arranged marriage is with…each other? …so now we have to pretend that we HAVEN'T been a couple for ages, since our families think we barely know each other and are assuming we'll both be violently opposed to this._

Relationships: Castiel/Dean Winchester

Characters: Dean Winchester, Castiel, John Winchester, Sam Winchester, other characters mentioned

Additional Tags: Alternate Universe - Fantasy; Alpha/Beta/Omega Dynamics; Omega Dean; Omega Castiel; Mating Cycles/In Heat; Mating Bond; Mating Bites; Anal Sex; Anal Fingering; Secret Relationship; Coming of Age; Somnophilia

Warning: Mention of rape, brief non-con scare but it's not actually non-con, mention of past underage sex

* * *

"Cas!" Dean had enough sense left to know that were he not so turned on, he'd be embarrassed by the mewling desperation in his voice. His hips hitched into every stroke of his hands, wrapped tight around both his and Cas' cocks, palm lubricated with a liberal amount of slick from each of them. Cas effortlessly slide a second finger into Dean's body, thrust in deeply, and Dean moaned. "Want you…"

"Can't," panted Cas, planting a sloppy kiss on Dean's chin. Dean's hand worked over their cocks faster and Cas groaned deeply. A single step forward pushed Dean back against the close walls of the dark storage closet, made it easier for Cas to press his hips into Dean's grip. His breath was hot and humid on Dean's neck and shoulder and, not for the first time, Dean's flesh tingled with the imagined sensation of Castiel licking his neck, sucking his scent gland, biting him hard enough to break skin. He wanted to beg Castiel to mate him, but he kept his silence save for ragged moaning gasps. Cas was right. They _couldn't_.

Cas' body trembled against his and Dean delighted in every small sign that Cas was close to climax: the urgency of his hips thrusting, the aggressive, uneven strokes within Dean's channel, the guttural base note accenting every breath he took. Dean wrapped his free hand around Castiel's back, encouraging Cas to rut their bodies together. Sliding his fingertips over the cloth of Cas' frock coat, down the curve of Cas' butt, Dean wedged his hand between Cas' clothed cheeks to palm at the place where Cas' slick had soaked through the fabric.

"Dean," Cas ground out, hips thrusting hard, the hot splash of release striking Dean's fingers. "Dean, I…I…" Dean didn't need to hear what Castiel intended to say, what Castiel always stopped himself short of saying. He knew. They both knew. Cas' movements stuttered to a stop as he finished; the pungent smell of his post-orgasm slick and semen filled the small space. The servants must know, couldn't possibly ignore the aroma when they retrieved their cleaning supplies, but they never said anything. Castiel smelled of vinegar and salt and a hint of orange, a tang that burned at Dean's nose and seared his body and, he knew, tingled through his mouth like the embodiment of perfection. The smell, the memories, Castiel's fingers finding the sensitive nub within him and pressing, all combined to drive Dean over the edge, tears leaking from the corners of his eyes as he collapsed back against the wall, hips working urgently into his hand and against Castiel's hand within him. His eyes fluttered open and closed, showing him gorgeous glimpses of Cas' intense expression, eyes nothing but black and white in the darkness as his gaze pierced Dean through, a possessive growl like nothing that should come from the throat of an omega rattling through them both.

Time stretched out as they stayed close, hard against the wall, breathing shallow and fast. Semen chilled over Dean's hand as he clutched their softening cocks.

"I have to go," whispered Castiel reluctantly.

"I do too," Dean sighed.

"When will I see you again?" Castiel asked.

Dean shook his head, dread and unhappiness threatening to dissipate the warm afterglow of finding release in Cas' arms. "I don't know. It might be a while."

Drawing away, Cas pulled a kerchief from his pocket, looked at his hand, thought better of wiping the slick away and instead placed it in his mouth and sucked, eyes slipping shut as if the taste were pure ambrosia. No force on earth could prize Dean's eyes from the delicious view and Cas didn't stop until every bit of slickness was gone; only then did Cas use the handkerchief to wipe away his saliva. Gently, he took Dean's hand and cleaned their semen away. With equal care, Dean tucked Cas's limp cock back into his breeches and buttoned the flap over the front.

"Soon," Dean promised. "As soon as possible."

Castiel rewarded Dean with a dazzling smile, opened the door, peered out into the hallway, and nonchalantly left as if he'd had a legitimate reason for spending twenty minutes locked in the servant's closet. It was an effort not to watch him go, but Dean couldn't risk being seen at the Novak estate. He took a moment to clean himself up, rebutton his breeches, straighten his frock coat. Clutching the strange, misshapen pendant of the necklace he wore, he murmured the familiar words of the invisibility spell and stole out through the tiny window. If he grew any taller or broader, he wouldn't fit through. It was bizarre to think he'd grown that much since he'd started sneaking over to visit Cas. Back then, they'd only been friends, meeting clandestinely because their parents couldn't be bothered to cover the couple miles between their homes as frequently as they wanted to meet. Whispered laughter and conversations had grown into shy exploration when they hit puberty, and embarrassment and uncertainty had faded quickly in the face of Cas' obvious interest in him and the extent to which Dean reciprocated. Neither had questioned that when they presented, they'd belong to each other. Sure, they'd be young for marriage, but stranger things had happened and they couldn't imagine their parents protesting. A union between them would join their neighboring estates into one of the greatest squiredoms in the kingdom.

It had never occurred to either that they'd both present as omega.

It was _bull_. Cas was no more an omega than Dean was an alpha. Cas was aggressive, domineering and possessive, and he always had been. It wasn't that Dean didn't sometimes display those traits, especially in defense of his friends, but Cas had always been the one to _growl_ and mouth at Dean's scent glands, even before they'd presented; Dean had always been the one to rough house and joke around and only to end up pinned to the ground, presenting, his legs spread wide, his cock achingly hard.

Dean made his way home over the rolling grassy hills that separated their two estates, dispelled the invisibility and tried not to drag his feet too much. Despite ample temptation and opportunity, Cas had never taken the final step, to take what Dean was offering, to thrust into Dean until they both wept in pleasure. There was no point. There was no future for two omegas in love with each other, no matter how Cas thought of himself, no matter how Dean thought of Cas. Biology didn't lie – no, that was bull, too – biology _did_ lie, but nothing Dean said John Winchester of that. _Cas doesn't have a knot, so he's not an alpha_. That had been the beginning and end of the discussion. Dean had never brought it up to his family again; Cas never tried to bring it up to his. Instead, they met as they could and waited for the other shoe to drop.

Tomorrow was Dean's 20th birthday. The other shoe dropped tomorrow. Alphas came of age at 25, by which point they were expected to have built a home and begun a career suitable to receive a spouse and support children. Omegas came of age at 20, indicating that they were mature adults ready to bear children. That was all that was expected of him. Dean wouldn't mind if those children were Castiel's but the prospect of giving up his freedom _and_ the only person he'd ever wanted was too much to bear. Not for the first time, Dean crested a hill, looked out over the sweeping, beautiful landscape dotted with rocks and copses of trees, and peered into the far distance in every direction save that of home. He could go to any of those places. He'd lose Cas if he left, but he wouldn't lose his dignity or his freedom.

If he went, Cas would be alone. When Cas turned 20 in the fall, he'd be married off too and even more miserable than Dean, forced to play an omega role that fit his body but not his spirit. Dean had tried to talk Cas in to leaving with him, but he refused, unwilling to go against the will of his father. Dean's arguments to convince Cas had been half-hearted. Michael Novak was strict but he loved his children, wanted what was best for them, and had always treated Dean as a member of the family. It would sadden Dean to upset the Novak patriarch, almost as much as it would upset Dean to disappoint his own father, but if he'd be with Cas it'd be worth it.

A thicketed ravine marked the last section of Dean's hike and as he finished he stepped onto the grounds of the Winchester estate the manor house came into view: imposing brick façade, large windows, and a single tower that once held cannon and now held his brother's telescope. In truth, he wasn't sure he could bring himself to leave anyway. John Winchester was over-protective to the point of insanity but it was only because he loved his children. If Dean played the good son as he'd always tried to do, maybe Sam would be allowed to spread his wings. There was a chance, anyway. At least Sam could be happy.

There was no point sneaking back in to the house. The spells John had put around the building meant Dean couldn't leave unattended, so instead he'd convinced Singer, the groomsmen, to cover for him on the many occasions Dean had snuck off to visit the Novaks over the years. It wasn't as if there were any _real_ danger; the kingdom was as safe as it had been in a century and what had happened to Mary Winchester was a fluke accident. Striding in, Dean was relieved there was no one to meet him, no one to scent the reek of his climax. Quickly, he returned to his room to clean up and change for dinner, but before he did so he went to the journal on his desk, opened it to page 66, and tried not to feel disappointed at the unsurprising revelation that it was blank. Grabbing a pen, he wrote, "I miss you already." The ink faded into the parchment and disappeared; it would reappear on the matching page in Castiel's journal and stay there until Cas read it. No response came immediately – they rarely did, unless both were reading the book at the same time – so he summoned a servant to draw him a bath. Cleaning up and changing his outfit left him feeling like a new man, but not in a good way. Covered in come and slick and Cas' dried saliva, Dean felt like _himself_. Cleaned and primped and dressed in fresh clothing that smelled of cedar and lavender, he was Dean Winchester, one day from becoming one of the most eligible bachelor omegas in the land and thoroughly miserable about it.

"I miss you too." The words faded as soon as Dean read them. He debated writing back and decided not to. What could he say that they hadn't said to each other a thousand times over?

 _I love you, Castiel_.

* * *

Zachariah Adler was an arrogant, entitled bastard. Margaret Masters was snide and condescending. Bela Talbot was pompous and self-absorbed. Aaron Bass was nice but a non-entity. Gordon Walker was a sociopath. The list went on: the wealthy, the titled, the successful; all alphas, all seeking Dean's hand. Among the landed and nobility, courtship was ritualized – the suitor solicited Dean's parents, was granted or denied permission to call, was invited to a formal dinner during which they were evaluated by the omega's parents. In Dean's case, that meant John questioning each like he thought them guilty of a crime, sitting like a king on his throne at the head of the table. Dean had been worried that John would be eager to get him married off, determined to find someone eligible at the earliest opportunity – preferably before Dean's next heat – with the expectation that a good, strong alpha could take over responsibility for keeping Dean _safe_. Instead, John's over protective nature worked in Dean's favor for once. There was something wrong with _everyone_. Bass was sent away for being diffident and agreeable; Adler was sent away for being confident and standoffish. The most recent, a fellow named Henriksen, Dean had actually liked, but Dean was nonetheless relieved that John didn't invite him back for a second meeting. For now, things were going as well as could be expected but sooner or later John would find someone he approved of and then Dean would be in trouble. He was under no illusions that _his_ opinion would matter when the time came.

With courtships occupying at least one evening every week, with John now on the lookout for any aggressive alpha willing to engage in the illegal to obtain a desirable omega, the few opportunities Dean and Cas had to meet privately evaporated. Over-protective at the best of times, John had Dean in lock-down. Even his rides with Singer were forbidden, the older beta considered inadequate protection for the desirable omega. The spells John used to protect the manor rendered it impossible for Castiel to enter without John learning of it, and even though they were both omegas they'd learned the hard way that John didn't appreciate _anyone_ sneaking into his estate, even the neighbor omega boy who had been Dean's friend virtually since birth. Dean and Cas had not been intimate in months. Even the book was silent depressingly often. Dean checked every night but Castiel rarely wrote him, and they were a long time removed from the nights when they'd shared everything on those pages even though they knew they'd see each other soon enough. Now, they were reduced to seeing each other only when their families formally visited. Because of the closeness between the Winchesters and the Novaks, that was still frequently – often more than once a week – but Dean was now considered an "adult," while Castiel was deemed a "child" though only months separated them, and it was no longer deemed appropriate for them to socialize. At least Cas wasn't an alpha. If he were, it'd be even worse – Dean wasn't allowed unsupervised time with any single alpha, lest instinct take over reason and lead to someone inappropriately claiming Dean without his family's say-so. As if Dean would ever let something that happen; he'd lay the person out if they tried.

 _If I can stop them…_

Dean had never felt further from Cas. To an increasing extent, Dean felt like he had nothing to say, and Cas had little to say in return. It was awful and made Dean feel abandoned by his best friend as well as his lover, left him wondering if he'd been wrong all along. Maybe Castiel didn't love him. It hurt to think it but Dean didn't know what other conclusion to draw. If Castiel reciprocated Dean's feelings, why wasn't he willing to fight to be together? Why wasn't he willing to leave? They'd never succeed. Michael or John would hunt them down wherever they fled, but they could _try_. Even Castiel expressing a willingness to consider an escape attempt would have reassured Dean and helped him get through the worst of the dinners: the night Walker had expounded for hours on what he considered the _proper place_ of an omega to be; the night Adler had managed to back him into a corner and feel him up before Sam intervened; the night Alastair Rolston had spoken with relish of his extensive collection of historical torture instruments; the night Abaddon Knight had spent hours looking at Dean like he was lunch, smiling all the while. At least John had recognized that none of them were suitable to be within 50 miles of Dean, much less become his spouse.

Dean didn't write about how alone he felt. He didn't write about how much he missed Cas. He didn't write about his fears for the future or his wish that Cas was an alpha or his desire to spend every day with his gorgeous friend or how every time he caught a scent of orange he turned around and was confused when Cas wasn't standing there. He didn't think Cas wanted to hear such things.

So he said nothing.

The early symptoms of Dean's approaching heat masqueraded as pique and displeasure. As he was generally piqued and displeased since he'd come of age, no one noticed the difference. It wasn't until the cramps started that Dean recognized his increased irritability for what it was. The first heat of an adult omega's life was considered cause for celebration. Most omegas were married by then and the expectation was that they'd come out of that heat heavy with child. Given that Dean was unattached, the less common protocols were put into place: near-total isolation. Dean was to be protected at all costs. Unattached omegas were irresistible to unattached alphas. In the more barbaric past Dean would have been fair game for any alpha of suitable social rank. The fact that he was _unclaimed_ was once considered a crime against society and would have brought his parents dishonor. If things were still such, even John Winchester would have found Dean an appropriate spouse before his heat. These days, things were supposedly more civilized. Alphas who claimed an unattached omega, regardless of the omega's age, regardless whether the omega was in heat or not, would face the full consequences of the law. Of course, that wouldn't restore the omega's dignity or virginity, wouldn't abort a pregnancy, wouldn't do away with any unwillingly formed marriage bonds. It was a wonderful _theory_ that there were negative consequences. The condemnation that heaped on a family that allowed their omega to be so taken advantage of was profound, compounded by shame that the omega had been violated and embarrassment that they had failed in their filial duty to protect their vulnerable kin. Most families would accept the match quietly rather than face the scandal. Even if they _did_ protest – Dean couldn't imagine that John would rape sanguinely, were such a fate to befall Dean – the law would intervene minimally and ineffectually if the alpha in question was of equal or higher rank to the claimed omega. If anyone got a hand on Dean while he was in heat, he was in trouble.

Knowing that intellectually didn't help him cope with the actual symptoms of his heat in the least.

Locked in his bedroom, Dean was left to his own devices and a guard on his door – John himself during the day, their family friend Ellen Harvelle at night. The hours were _endless_ , spent alone except when Sam brought him meals. Dean rubbed his cock raw, fingered himself to distraction, but it was never enough. This was not his first heat; during rare moments of lucidity he knew what he was experiencing was comparable to his previous heats. The symptoms would pass in a week or ten days and not return for four or six months. Such moments of lucidity were few and far between, though, occurring only for short periods after he managed to tease an orgasm from his desperate body. Climaxing was nearly impossible without a partner. He clawed at the door and begged, he screamed for release, he sobbed into his pillow in abject frustration, and he dreamed of companionship and longed for Cas.

Dean had stopped looking at the blank page of the book. It hurt too much to have constant reminders of Cas' apparent indifference. His thoughts screamed for him to write, to beg his friend for help, but the distance between them was insurmountable.

With no hope of contact with the real man, Dean lost himself in dreams.

 _Hot lips on mine, a body stretch over me, a knot stretching me, a hand on my cock_.

The fantasies were incoherent as dreams are wont to be, a jumble of discordant images. One moment he was begging, pleading to his silent room for a knot, and the next Cas was on him, Cas was in him, Cas was tugging his pants down and thrusting into him easily and biting his neck so hard he screamed in pain. He'd blink and when his eyes opened again Cas was atop him, mouth locked open in a silent _ohhh_ of pleasure as he took Dean quietly and gently, as, in the context of the dream, he had a hundred times before. Only when Dean awoke again was he cognizant of the fact that Cas wasn't there, that Cas had _never_ filled him, that Cas didn't want to fill him any longer. In the dream, it was all real, it was all he wanted, it was forever. Cas was his mate. Reality was harder to face when he once again sat alone in his room trying to alleviate the heat and misery suffusing him to the point of nausea.

 _Hands palmed at Dean's chest, lips followed in their wake, soothed then bit then licked then massaged. Dean's cock brushed against his belly, smeared thin liquid that pooled until Cas reached that spot and sucked it up, kept sucking until Dean was bruised and aching, ignoring as Dean pled for Cas to give him the relief he needed_.

The days and the nights blurred together. Dean had no idea how far into his heat he was and there was no one to tell him. Only family members and mated omegas were considered trustworthy around an unmated omega in heat. A mated omega, such as an omega parent, might stay with Dean and aid him, but lacking such a person Dean was on his own. Mary had died before his first heat and there wasn't a single mated omega in the household of high enough social standing to guide him. Sam pushed the limits of respectability by helping Dean eat his meals, and that was the only contact he had with the outside world. He lost count of how often Sam visited; he only knew that it was more than he could easily remember, each time blurring together.

 _A clatter fractured Dean's thoughts like a crack of thunder, frightened him, left him mewling, unsure if he was more aroused or distraught. Soothing hands cupped his face, a well-loved voice whispered, "it's okay, you're okay, I'm here now." Pleasure beyond anything Dean imagined flooded his mind, his body. He couldn't move, couldn't answer, all he could do was bathe in Cas' presence and touch and scent._ My mate _, Dean's thoughts insisted._ My mate is here.

 _Hot kisses scattered over Dean's face, his shoulders, his neck. Hands touched him everywhere, leaving seared, twitching flesh in their wake. "Beautiful…smell so good…missed you…miss you so much…"_

" _Miss you," Dean echoed, mumbling. "Love you."_

 _His ears filled with the sound of growling. Cas' body enveloped his, rutting, whispering incoherence in his ear, guttural noises that Dean reveled in._

 _The heat was gone, the weight was gone, but the scent remained to reassure Dean that he wasn't alone. He lay on his stomach, cock trapped between his stomach and the bedding, hands wringing uselessly at his blankets._

 _A single finger traced his crack, slid smoothly down the delicate skin smeared with slick._

Dean's bedroom was over-warm, as it had been continually since his heat started and he half-woke up to moonlight streaming brightly through his window. He was already panting, body overwrought and desperate and unfulfilled. Whimpering, he rutted against the mattress, seeking relief, but there was none to be found. _I wish my mate was here. I wish Cas was here_. The air was so thick Dean thought he could smell Castiel; the smell made Dean feel lonely yet safe, protected, in good hands. His eyes slid shut again, exhaustion tugging him under once more even as he lazily fingered himself with one hand.

" _Don't worry, I'll take care of you," whispered Cas' deep voice, taking Dean's hand away from where it worked at his hole._

 _Incandescent light exploded in the room, burning away the drapes and floor coverings, vaporizing the unlit logs in the cool fireplace. Dean couldn't understand how his bedding wasn't in flames, how the entire house wasn't incinerated. Maybe it had been, maybe he was dead._

 _Hands on his butt cheeks spread him wide._

 _There was soothing warmth around his hole, something firm and strong_ inside _him, a sucking feeling, a vibration that resolved in his sluggish thoughts into the sound of Cas growling, the sense that somehow Cas was growling inside his body. Dean could feel the possessive noise as a touch along the skin behind his balls, the sensitive rim of his pucker. It echoed through the most sensitive places in his body and he screamed with the pleasure of it, screamed at the relief that finally, someone was giving him what he needed, someone was going to give him_ everything _that he needed._

" _You have to be quiet," Cas breathed heavy against Dean's skin. "If I'm caught here, now..."_

" _Oh, Gods, Cas," moaned Dean, squirming against the bedding, pressing his butt back into Castiel's face. "Gods above, don't stop, don't stop..."_

"Fill me, Cas, please fill me, I need you so much, no one but you, only you." Dean's mouth was dry with the cottony taste of the bedding his face was pressed against. He was more aroused than could ever remember being, agonizingly so, his discomfort and misery the worse for realizing that he was awake and alone and...

...two fingers thrust easily into his loose hole and he howled as they spread him, stuffed him full, brushed over the sensitive nub inside him, promised him the thick cock he needed. Panic followed a moment later, eating at his thoughts, threatening even his pleasure. Despite every precaution his family had taken, someone was there, someone was with him, when Dean was too incapacitated by need to fight back. Even as his thoughts rebelled and fear twisted his stomach, his body craved a knot, his lips continued to leak needy, broken pleas. The fingers thrust within him, slick oozing out around them as they were withdrawn, his body stretching wide as a third was added.

"Feels so good, so good...I need you, need...good...no, stop..." Gods give him the strength to not beg for the hand that took him involuntarily! "Stop, stop, stop..." He repeated the word as a mantra, feeling stronger and more aware the more times he said it. The fingers within him froze, withdrew, and the apparent obedience of the person with him helped Dean regain control of himself. He squirmed away, body achingly empty, and forcing himself up the bed and away from his attacker.

"Dean?" asked a hesitant voice. Blinking tears from his eyes, Dean took in a vision of perfection. Moonlight picked out the clean lines of a gorgeous, lithe body, highlighted a beloved face in shades a white and gray and black, cheeks flushed dark gray, lips pale, eyes twinkling and dark. _Cas. It really is Cas_. "I'm sorry, I thought...?" A tentative hand reached towards him. "You begged for me...you _begged_...I thought you still wanted...I shouldn't have come, I shouldn't have..."

"Cas?" Dean asked, terrified that he was still dreaming. "How?" He smelled like Cas, the whole room smelled like Cas, and suddenly the answer didn't matter. Dean's fear melted away, melted into bliss, and he threw himself at Castiel, knocked Cas back against the footboard of his bed, smothered Cas' mouth with kisses, seized Cas' hands and wrapped them around his bare bottom.

"I'm sorry," Cas managed as Dean mouthed at his chin, his cheek, his lips. Shifting to straddle Cas' waist, Dean ground down against Cas' cock and they both groaned. "I've been planning for months, I should have told you, I'm a—"

"Shut up and do it," snarled Dean.

"Wha—"

"Do _me_ ," Dean clarified. Cas' eyes went wide, his body still, and Dean bit back more angry words, instead seizing what he wanted. Canting his hips forward, shoving his erection hard against Cas' belly, Dean ran his slick butt over Cas' cock, moaning each time the hard tip caught his rim.

"I came to mate you, Dean," Cas panted. His hips rolled into each pass, his hands tilting Dean's hips, trying to get the angle right so that their bodies would join. "If someone..." He moaned, soft and low. "If someone mates you during your heat...even if it's an omega like me..."

"Not an omega," grunted Dean. Slickness guided Cas where Dean needed him and instead of sliding over, Cas caught, pulled on Dean's rim, and his dripping pucker welcoming the thick head of Cas' cock. Cas' eyes squeezed shut, his hands went tense on Dean's hips, and he trembled with the effort of holding himself still as Dean lowered himself slowly.

"Everyone thinks I am," Cas breathed. Nothing felt like having Castiel stretching him, straining within him, gliding easily on his slick. He moaned praise and pleasure as he his thighs came to rest on Cas' legs, Cas' cock buried within him.

"No," groaned Dean, shimmying his hips to adjust their position, to get Cas deeper within him still. "Alpha." Cas moaned, leaned forward and wrapped his arms around Dean's back, gripped Dean's shoulders, arched their bodies together, shuddering and shivering with pleasure. " _My_ alpha." This was what Dean needed, what he'd _always_ needed. Satisfaction swirled in his gut; the out-of-control sense that nothing would ever be enough faded and in its place was instinct driving him to move, to drive to feel Cas slide within him. Shifting his weight, he rose uncertainly on his knees. The rub of Cas' cock through him was exquisite, fired bliss through his blood, and he slammed back down to replicate the sensation.

"Dean!"

"Fill me, alpha," Dean growled, rising and dropping again, picking up a rhythm. Cas clung to him and shook like a leaf in a gale.

" _Dean_!"

"Knot me, alpha!" From the first, he'd felt hotter than he ever had before, and with each stroke the feeling intensified. He wasn't sure how the room didn't burn up as it had in his dream. Cas panted against him, struggling to meet each of Dean's thrusts.

" _Yes_ ," snapped Cas. The moonlight caught in his eyes like a starburst as Cas surged forward, rolled Dean onto his back, Dean's legs held up and to the sides, and slammed his hips hard into Dean's body. Dean's vision of the room went blank; he had no idea if his eyes were open or closed, all he knew was there was nothing but pleasure filling the world.

"Love you, Cas," he gasped. His body clenched, seeking more; with his muscles tight the feelings amplified, Cas thrust into him again, and Dean snapped, involuntary spasms wracking him, his cock spurting hot between them.

"My Dean," Cas groaned, hips jerking. "Mine, always mine..." Through a handful of stuttering strokes, Cas worked against his body and then collapsed limply, panting, each exhale loud in Dean's ears. His lips played loosely over Dean's neck, sucking and licking, but no bite came. Dean felt the absence of the connection as tight, binding pressure around his chest. He couldn't get enough air; he was painfully aware of his racing heartbeat. Wrapping his arms around Cas, he caught the back of Cas' head and pressed him encouragingly against Dean's neck.

"Not yet," murmured Cas.

"Why not?"

"Want you to be sure," Cas said. "Want you to _know_."

"I _do_ know," Dean insisted. Cas shook his head. "Please, Cas!"

"I love you, Dean," breathed Cas in his ear, starting to calm. The vise-like press around Dean's ribs eased. "I've always loved you. I can wait a few more minutes until your head has cleared enough for us to talk about this."

Suiting action to words, Castiel slid from atop Dean's body to lie beside him, one arm wedged between their bodies, the other wrapped around Dean's chest. Release and slick cooled unpleasantly on Dean's stomach and between his legs, and though Cas couldn't knot him Dean still felt better than he had in days. His body was sated. Curling to his side, he pressed his back to Cas' chest, slotted Cas' soft cock between his legs, sighed happily at how nice it felt to have Cas wrapped around him. This was the kind of intimacy they'd rarely been able to share and it was everything that Dean wanted. If he could awaken to this every morning, go to sleep to this every night, life would be perfect.

"Do you think our parents would will allow it?" Dean asked when the silence had stretched out as long as he could bear.

"If we've made the bond, will they have a choice?" Cas countered.

"Do you think the bond will work, considering…?" Dean left the rest unsaid. He would never let the words _considering you're an omega_ pass through his lips. Dean didn't believe Cas an omega, knew Cas didn't think of himself as an omega, but they both knew that Cas' body indicated otherwise. Saying the words aloud would hurt Cas, would shake his confidence, would damage his faith that Dean believed in him.

"I don't know," confessed Cas. Hurt was evident in his voice even though Dean had held back, and he cradled Dean more closely, pressed a palm to Dean's heart.

"Why're you here, Cas?" It wasn't what Dean wanted to say; he wanted to ask to be joined, wanted to try, wanted to focus on the past half-hour and not dwell on the long division preceding it, but he had to understand before he could give permission. They'd hardly spoken for months, hardly seen each other, and Dean felt the weight of those days and weeks heavy on his heart.

"It's the only way," Cas said. "If we'd run away, they would have found us and made us marry other people." _Made each of us marry alphas…Gods, how would Cas cope with that?_ The idea of Cas submitting to anyone, of opening himself to a knot, disgusted Dean; it must horrify Cas, though he never said anything about it. "I wanted to talk to you but you've been avoiding me. You didn't even answer my notes in the book, I just didn't know what to think…"

"You didn't write in the book!"

"Of course I did!" Cas protested. "Starting weeks ago, when I realized there was no chance of us speaking when our families met." Guilt wracked Dean. He'd given up on trying to steal time alone with Cas, he'd given up on checking to see if Cas had written. All the time he'd been angry with Cas for abandoning him, he'd been as much to blame, he'd abandoned Cas.

"I'm sorry," he whispered, cuddling closer to Castiel's warmth, wrapping his hand over Cas'. "I'm so sorry, I don't deserve—"

"I couldn't get you to talk to me, so I talked to Sam," explained Cas gently, no anger in his voice, and Dean felt even worse. "He told me about the suitors, about how worried he was for you, about your impending heat. I told him my plan and he said he'd help get me in the house. That's why I'm here – that's how I'm here. Your brother and Ellen let me in so that I could take care of you during you heat, so I could mate you before John decides the only way to keep you safe was to lock you in here forever, before I turn twenty next month and Michael finds a nice alpha to show me how an omega should be behave."

"Mate with me, Cas," Dean said. Cas shivered, brushed a kiss over Dean's shoulder.

"Are you sure?" breathed Cas. Dean nodded carefully so as not to knock his head against Cas' face. "Okay…" Lips sucked over the sensitive scent gland on Dean's neck and Cas moaned deep in his throat, nipping at the flesh. Dean whimpered, rutting his hips back as he felt Cas began to grow hard against him, his channel growing slick and hot once more. "Okay."

Where their earlier sex had been frantic, spurred on by Dean's desperation, this time was slow, gentle, brought Dean a profound understanding of why it was called _making love_. Cas worshipped Dean with his body, touched and praised him, teased and pleasured him, filled him and rocked their hips together until Dean had no idea where he ended and Cas began, never _wanted_ to know where that difference lay, hoped he'd never have to experience such division again. Tenderness and love marked every one of Cas' actions, and for once Dean didn't seek to give back as much as he got; instead he listened to Castiel's soothing words, his promises of love, and allowed himself to be cared for.

Pleasure built slowly, growing long after the moon had set over the distant hills, until Dean reached a peak even higher than he'd achieved earlier, his body shaking, his wetness leaking through the sheets, his face streaked with sweat and tears, his lips mouthing Cas' name over and over again. Only then did Cas mouth over Dean's neck, down his clavicle, to lick over his scent gland. Only then did Cas whisper again that he loved Dean, thrust into him hard and bite down, breaking skin with his sharp canines. Only then did Dean shake apart, muscles tensing and then melting as he splattered release all over his and Cas' bellies. Cas choked against the bite, sucking in Dean's blood even as he came in Dean's clenched ass, gagging as he tried to complete the bond while climaxing. When he stilled, Dean pulled Cas up from the bite, adoring Cas' slack, bemused expression. Scenting Castiel's neck, mouthing over the skin, Dean let the burn of vinegar and citrus dance over his tongue. _Perfect, this is perfect; this is exactly what I want_. Catching a fold of skin between his teeth, Dean nipped hard, broke skin, sucked Cas' blood into his mouth. Speechless, Cas shuddered and climaxed again, filling Dean so much with release that he felt it as pressure within him, so intense, so satisfying that he moaned and came again as the taste of copper and Cas flooded his senses.

Sunlight rendered the room gray before either of them moved; they lay awake for hours, Cas' sweat-slicked body drying as he lay atop Dean, both gently mouthing and licking at their new-made bites. They were so still that Cas' cock only slipped out of Dean's body because he'd grown soft. Dean had no idea what a mating bond was supposed to feel like. Romantic stories spread by the type of tittering alphas and omegas he'd always avoided suggested it was perfect awareness of one's mate, the ability to read their mind and share everything with them. Dean doubted that was accurate but he felt nothing even close. As the emotional high wore off, he tried not to fret at the absence, tried not to obsess and worry if the bond would take. By dawn Dean's fears had faded. Castiel was giving him a dopey, broad smile, his eyes glowing in the bright light streaming through the window, and Dean could _feel_ Castiel's contentment radiating out, feel it as surely as his own happiness and relief and reviving arousal. It was awareness of another person as he'd never experienced it before, not as profound as the stories said but still glorious, and he knew they were going to be fine.

"I love you," he whispered, repeating the words so he could bask in the answering brilliant glow of Cas' love and pleasure and satisfaction. It was a feeling that would never get old.

* * *

A knock on the door warned that Sam was about to come in. There wasn't time for Cas to hide effectively, so instead he rolled off the bed to lie on the floor on the far side of it, out of sight from the doorway should John glance in but sure to come into the view of anyone who entered. Fortunately, John only peeked through the barely-cracked door, saw Dean hastily covering himself with a blanket, sighed and closed the door behind Sam. Sam heaved a relieved sigh as soon as he was inside, set the breakfast tray atop Dean's chest of drawers and smiled as Cas stuck his head up beside the bed, the fresh wound on his shoulder impossible to miss.

"You two are okay?" Sam whispered, eying the door.

"Yeah, Sammy, we're good," Dean said. He gave his brother an affectionate smile. Everything was _wonderful_. Dean felt better than he recall ever feeling before, the sense of well-being and happiness bouncing back and forth between him and Castiel and amplifying every time until it seemed impossible that either of them might ever feel sad again.

 _Of course, if he or I_ were _upset about something, or if both of us were, presumably that would echo and grow similarly…_

"Thank you," added Castiel.

"Now what?" Sam breathed, a relieved grin showing his teeth.

Castiel and Dean exchanged a look. They hadn't thought about what came next. "They have to find out sooner or later, right?"

"So, sooner or later?" asked Dean.

"How about sooner?" suggested Cas, shrugging.

"Works for me," Dean shrugged as well. "I don't know about your parents but dad'll be less upset about it if I'm still in heat."

"So….?"

"Discover me, Sam," Cas said.

"Excuse me?"

"Be scandalized: you've just discovered a man, uninvited, in your brother's bed chamber during his heat. I think horror is an appropriate reaction."

"You could scream," Dean chimed in helpfully. Sam scowled at him.

"I am _not_ screaming," said Sam, testy.

"Shriek, then?"

"Dean—"

"However you care to react, as long as it's believable," Cas cut in.

"Maybe you could, I dunno, startle me? I mean, it's weird to just…react…when I'm not surprised?" said Sam.

"If you screamed you wouldn't have that problem," Dean pointed out. Cas disappeared from view behind the bed.

"I am _not_ screaming," Sam said with annoyance. "I—" Sam screamed, Cas stuck his head up from beneath the bed with an impish smile, and the door slammed open to reveal John, sword in hand as he stormed into the room.

"Dean! Sam! Get down!"

Pandemonium erupted. Sam did an excellent job of acting _utterly_ shocked and confused at the discovery of Castiel; Dean intended to look suitably chastised and embarrassed but – as Sam told him later – mostly looked constipated; and Cas didn't have to pretend fear as he fled across the small space, trying to avoid John's rage. Dean's legs were weak, his body achy, but he forced himself up, importuning John to relent. Cas was trapped in the corner of the room and John showed no signs of slowing or calming long enough to listen to explanations. Hoping to soothe his father's temper, interjected himself between his father and his mate, lifting his hands restrainingly. Unfortunately, Dean's actions had opposite the intended effect; John's fury doubled when the blanket haphazardly wrapped around him fell away and revealed his mating bite. With a cry, Sam threw himself on John's back even as John raised an arm to sweep Dean out of the way and have at Castiel with his sword.

"If you hurt him…" Dean snapped, but the words lacked bite. Dean was too weakened by his heat, too tired after the long night, to be a threat. Standing between them, he swayed as if moved by a breeze, legs aching and butt and back sore, eyes gritty, slick beginning to leak free despite the awkwardness of the moment. _I'm in trouble._ Even at the best of times, he couldn't conceive of winning a physical fight against his dad, but for Castiel he'd try.

"Stop!" Castiel was much more successful at sounding threatening, a stern note of command in his voice that brought John up short.

"Excuse me, boy?" demanded John warily.

All sense of fear was gone from Cas' face and voice. He stood up straight, grabbed Dean's hand and took up a bold position in front of Dean, inserting himself between Dean and his father despite Dean's strangled protest. Naked, unashamed, and radiating fury that Dean found oddly comforting, Dean could hardly believe Castiel wasn't glowing with the power and command he projected. Cas gave Dean's hand a reassuring squeeze. "While you posture, Dean is suffering. If you don't care about me, despite a lifetime of acting as if you did, then for _his_ sake will you _please_ calm down?"

"Your damn right he's suffering," John snarled. Sam was still latched onto John's neck, but John ignored him. "After what you did to him, you—"

"No," interrupted Dean weakly. John started and glared at him. Wilting, Dean pressed against Cas' back, feeling small and unfamiliarly helpless beside Cas' show of dominance. "No, dad. This is what…Cas is who I want." John's angry expression faded confronted with Dean's obvious distress.

"He's not an alpha, son, and he's just a kid," said John, exasperation taking over in place of his temper. "He won't be able to protect you. He won't be able to take care of you." Sam locked an arm around John's neck, drawing a grunt. "Lemme go, Sam."

"You gonna hurt Cas?" Sam demanded

John looked from Dean to Cas and back. "No," he sighed. He emphasized the point by sheathing his sword. Sam released his grip and settled back on his heels. "Dean…Cas…put some damn clothes on. We need to talk."

Without answering, Cas stepped back, put an arm around Dean's waist and helped him back to bed. The sheets were disgustingly soiled after their night together, but with some arrangement Cas made Dean a nest of pillows and a spare blanket and Dean settled gratefully onto the bed, his body screaming protest after the short period he'd spent on his feet. At least he was no longer burning up; his night with Cas had done wonders for tempering his heat.

 _I might be pregnant_.

He pushed the thought aside as Cas retrieved Dean's blanket and spread it over him. Through it all, John watched, eyes narrowed. Only when Dean was comfortably situated did Cas gather his belongings from a neat pile beside Dean's bed and cloth himself without a trace of self-consciousness. When he was clothed he took a seat beside Dean a modest distance away. Dean scowled, ignored the stares of his brother and father and slumped across that distance to rest his head against Cas' shoulder. The instant they were in physical contact, even with cloth separating them, Dean felt better. Tension drained noticeably from Cas, as well.

"Boy, when Cas presented you asked me about this and I said _no_ ," John said. "End of discussion. Shouldn't even be possible for two omegas to partner. I mean, Cas can stick his cock in you all he wants, might even get you pregnant, but he can't knot you. Bite each other 'til the end times if you want, you won't be able to mate."

"We bonded, Mr. Winchester," said Cas firmly, wrapping an arm around Dean's shoulders to draw him closer. Dean sighed into the contact, molding himself along Cas' side. Contact was exactly what he needed. His heat was stirring again despite his fatigue and his empty stomach; he hoped that John would give them some privacy before he reached the point that he couldn't control himself, before he needed Cas so badly he'd mount him without a care for who saw.

"Prove it," said John. He sounded skeptical, but he was clearly listening. _We get one shot at this…_

"Isn't the fact that Dean isn't delirious with heat proof enough?" Cas suggested acidly.

"It's proof that you had sex," John replied bluntly. " 'Any cock in a storm,' my granddad used to say. Sure, getting some from another omega is unusual, but it's not unheard of. Doesn't mean a thing related to the bond, though."

"Cas is angry right now," said Dean abruptly.

"Any idiot can see _that_ , son—"

"But he's also worried," Dean interrupted. "He's worried about how much stress this is causing me, he's worried that you're going to say no, he's worried that his family is going to say no. He's horny, too; he can smell that my heat is starting to surge again, which makes him worry more – what if you haven't left by the time I need him again? – but it's also getting his heart rate up. He's trying to act reassuring to keep me from worrying too. He's actually kind of succeeding."

"I'm glad," murmured Cas, stroking a hand up and down Dean's side. "I _will_ take care of you, Dean. I'll protect you from _anyone_ who tries to take you from my side."

"None of that is proof," John scoffed.

"Dammit, dad, what do you _want_ from them?" Sam cut in. "Can't you see that they're in love? Leave it be!"

"You'll keep your mouth shut and outta things that don't concern you!" John rounded on Sam. "Be thankful that I don't ask how Cas got into this house when I had it on full lock down, cause I know _Dean_ didn't let him in, and Cas sure as hell didn't get past the wards himself!"

"If you hadn't been such a stubborn _jerk_ about this, I wouldn't have had to!" Sam shouted back, denying nothing. "What, you'd rather see Dean with Gordon Walker? Or that Abaddon woman? _Alastair Rolston_?" Dean shuddered and buried his face against Cas' shoulder. Thinking of the other alphas, the way they'd looked at him, they way they'd smelled, sickened him. Unhesitatingly, Cas wrapped both arms around Dean, making soothing noises. Dean could feel Cas attempting to suppress fury that other alphas had upset _his mate_ , suppressing worry that some stranger might have attempted to claim Dean had Cas not come to protect him. "Who _cares_ if the bond worked! Just _look at them_!"

"I have been," admitted John reluctantly. Dean felt a flare of hope; he had no idea if it originated from himself or Castiel but it grew stronger, brighter, until he couldn't keep his excitement at bay, couldn't keep a smile from his face. "It's gonna take me some time to get used to this, but for now – Cas, you can stay. Dean clearly needs you to get him through the next few days. I'll call on Novak and let him know not to panic when he realizes you're missing. There's gonna be hell to pay for this," John concluded, shaking his head.

* * *

As was often the case, John Winchester was wrong. There were no consequences for Dean and Cas' unusual liaison. On the contrary, everyone the kingdom over ignored it as much as possible. Any annoyance that Michael might have felt at being denied the opportunity to marry off his son went away as he realized that what prestige he'd lost without the marriage, he'd more than gained when suddenly his omega was promoted to being an alpha. Society could not bring themselves to believe that two omegas could mate – it went against everything that everyone believed about how mating worked – and found it more agreeable to believe that they'd all been mistaken about Castiel all along. Dean was _obviously_ an omega – his pregnancy made that impossible to doubt – and that meant that Cas _obviously_ was an alpha. It was such an inescapable conclusion that no one talked about it more, there was no public wedding, there was no formal announcement, there was no presentation to the king. There was as little fuss and pomp as anyone could remember ever seeing attendant on the marriage of two such important people. Rather than risk discussion of the _actual_ reason that was the case, everyone pretended it was normal, blamed the usual factors ("well, you know how it is when an alpha claims an unmated omega in heat") and moved on.

Having the world see Cas as an alpha suited the couple fine, as it had been their understanding all along. Even without a knot, Cas had no trouble keeping Dean satisfied, and Dean proved as fertile as they could hope, giving them a child a year regular as clockwork. John and Michael were both delighted at the horde of grandchildren. The future of both estates was guaranteed, the marriage of the elder siblings helped ensure the eligibility of the younger, and Castiel and Dean both stood to inherit their fathers' estates when the time came.

It wasn't a happily ever after. There were dark clouds, plenty of them, but they tried not to dwell on those. Sometimes, that was easier than others, but at the end of the day they always had one simple truth to fall back on.

They were _together_.

* * *

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